function configSet($key, $value, $layer = 'user', $channel = false)
{
$this->config->set($key, $value, $layer, $channel);
$this->_preferredState = $this->config->get('preferred_state', null, $channel);
if (!$this->_preferredState) {
// don't inadvertantly use a non-set preferred_state
$this->_preferredState = null;
}
}